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Smog stuff removal

Green Monster

Green Monster

1/2 ton status
Joined
Aug 10, 2013
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Location
Thousand Oaks, CA
So it's clear that my 76 K5 wont pass smog, and since I have the air pump off, I may as well take everything else off. A few questions:

- There's a vacuum line that goes from the carb to the air pump. What do I do with it?
- I'm going to just run a hose to connect the two manifold air lines. That's ok, right?
- Do I need an idler pulley to triangulate the alternator belt? Or just get a shorter belt?
- I understand I can delete the EGR, and install a plate. What do you think?
- There's some sort of valve/contraption attached to the water hose thing on the manifold. I had to swing it out of the way to make room for the new fuel line. When I loosened the bolt, coolant came out. There's a plunger type thing on one side, a vacuum line, and what looks like a broken metal line on the back. I attached a picture, and as you can see, I rotated it counter clockwise so it wouldn't hit the fuel line. Other than rotating it, it is as it has been since I bought it. And it runs fine.
- What else can I remove? Any other non-necessary vacuum lines? Figured I'd leave the charcoal canister, not hurting anything.

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If it won't smog, how will you register it in Komifornia?
 
Just asking cuz the trailer thing gets old?
 
It has most of the stuff needed to pass, but I can't find the preheater stove assembly that attaches to the exhaust manifold. And looking at the vacuum lines, it's questionable at best. So I'm done messing with it. It's still registered, I just can't get my stickers. No big deal.
 
Rip everything off and plug it except the vac advance. Don't leave any hoses not running something

Loose the air pump and short belt. Dump the cats and EGR. Use the charcoal canister to the tank vent
 
Bent77 said:
Rip everything off and plug it except the vac advance. Don't leave any hoses not running something

Loose the air pump and short belt. Dump the cats and EGR. Use the charcoal canister to the tank vent
Click to expand...
Thanks. So what is that valve thing I mentioned that's in the picture?
 
That valve might be for spark advance? I don't think that early they were doing anything with the trans and vacuum/temp.(?)

Be aware that you need to understand how everything works beforehand (what switches control what, hot or cold, where the vacuum lines run, etc), if you plan on yanking *most* of it off. All the thermal vacuum switches, check valves, y's, etc are all tied together. If you don't understand how it works, the Evap may never purge, or if that valve is indeed spark advance it may be in the wrong position to get proper advance when warm, etc.

This is really where TBI swaps shine. Everything is either electrically switched, or non-existent. Far cleaner.

If it's offroad only, not using EGR likely won't be noticed, but the carb will run lean at part throttle unless you tune for lack of EGR. It probably will if Evap isn't plumbed/timed right too, but I'm guessing that's much less an issue than EGR. I know EGR will cause a lean surge, because I did the same thing back in the day.
 
dyeager535 said:
That valve might be for spark advance? I don't think that early they were doing anything with the trans and vacuum/temp.(?)

Be aware that you need to understand how everything works beforehand (what switches control what, hot or cold, where the vacuum lines run, etc), if you plan on yanking *most* of it off. All the thermal vacuum switches, check valves, y's, etc are all tied together. If you don't understand how it works, the Evap may never purge, or if that valve is indeed spark advance it may be in the wrong position to get proper advance when warm, etc.

This is really where TBI swaps shine. Everything is either electrically switched, or non-existent. Far cleaner.

If it's offroad only, not using EGR likely won't be noticed, but the carb will run lean at part throttle unless you tune for lack of EGR. It probably will if Evap isn't plumbed/timed right too, but I'm guessing that's much less an issue than EGR. I know EGR will cause a lean surge, because I did the same thing back in the day.
Click to expand...
Thanks, so can I get rid of that spark advance thing? And will it be fine just running the alternator to the crank, no idler pulley? And if I just plug the misc vacuum lines not being used, is that OK? Per the post above, do I just need the vacuum advance? Sounds like I should just keep the EGR, since I don't know how to tune a carb.
 
I didn't say get rid of the spark advance thing, I said I wasn't positive what it was, and that you need to know how the system operates before yanking it off. Making an example out of thin air, if it's a thermal vacuum switch (TVS) connected to the distributor, and it retards timing 10* until coolant hits 195*, what happens if you gain 10* of timing across the board when the engine is cold? Don't know, but I'd guess it may impact how it runs.

My alternator belt runs the water pump and off the crank. Pretty sure two belts drive the water pump (power steering and alternator) on my setup, so I suspect it's a bit of redundancy, or necessity to ensure the pump pulley doesn't slip. Or, you can't fit a belt to the crank without hitting the water pump pulley.

You don't NEED vacuum advance, it's just nice to have under certain conditions. The circle track cars I'm familiar with that run old timey small blocks don't use vacuum advance.

Plugging vacuum lines is a necessity, you can't leave them open, generally. Only options are to leave them alone, disconnect and plug them, or leave them open.

If you keep the EGR, are you sure it will operate properly without being controlled by engine temp? I do not know the answer to that question. It probably will, but who knows for sure?

Running off-road, you'd likely never notice the lean surge from EGR. It's at part throttle cruise where EGR is normally used. It's not like it makes the vehicle impossible to drive, it was irritating in my opinion when I experienced it.

Can you even sell the vehicle if you can't smog it? This seems like a lot of hassle for a missing heat stove that can probably be purchased for $20 or so.

Without exception, I can tell you that trying to put all this stuff back in place will be exponentially more costly and larger hassle than keeping it operating properly now. Until the adoption of EFI by GM, emissions sucked. The 70's and 80's were horrible, and I'd rather spend the effort to convert to EFI than spend an hour working on the carbed emissions setups. Because not only would I be able to pass smog without question, I'd have a vehicle that drove more like a modern vehicle, and a cleaner engine bay to boot.
 
dyeager535 said:
I didn't say get rid of the spark advance thing, I said I wasn't positive what it was, and that you need to know how the system operates before yanking it off. Making an example out of thin air, if it's a thermal vacuum switch (TVS) connected to the distributor, and it retards timing 10* until coolant hits 195*, what happens if you gain 10* of timing across the board when the engine is cold? Don't know, but I'd guess it may impact how it runs.

My alternator belt runs the water pump and off the crank. Pretty sure two belts drive the water pump (power steering and alternator) on my setup, so I suspect it's a bit of redundancy, or necessity to ensure the pump pulley doesn't slip. Or, you can't fit a belt to the crank without hitting the water pump pulley.

You don't NEED vacuum advance, it's just nice to have under certain conditions. The circle track cars I'm familiar with that run old timey small blocks don't use vacuum advance.

Plugging vacuum lines is a necessity, you can't leave them open, generally. Only options are to leave them alone, disconnect and plug them, or leave them open.

If you keep the EGR, are you sure it will operate properly without being controlled by engine temp? I do not know the answer to that question. It probably will, but who knows for sure?

Running off-road, you'd likely never notice the lean surge from EGR. It's at part throttle cruise where EGR is normally used. It's not like it makes the vehicle impossible to drive, it was irritating in my opinion when I experienced it.

Can you even sell the vehicle if you can't smog it? This seems like a lot of hassle for a missing heat stove that can probably be purchased for $20 or so.

Without exception, I can tell you that trying to put all this stuff back in place will be exponentially more costly and larger hassle than keeping it operating properly now. Until the adoption of EFI by GM, emissions sucked. The 70's and 80's were horrible, and I'd rather spend the effort to convert to EFI than spend an hour working on the carbed emissions setups. Because not only would I be able to pass smog without question, I'd have a vehicle that drove more like a modern vehicle, and a cleaner engine bay to boot.
Click to expand...
I'm keeping all of the smog stuff in case I need it. And I'm not making any permanent changes. Temporary fix till the motor blows, then will go the LS route, or even TBI depending on funds. I'll never sell it. And if you can find me a heat stove for $20, I'll take it! I've searched high and low. I have the tube, those are easy to find. It's the contraption that is riveted to the exhaust manifold. Nowhere to be found.
 
Ok, here is my solution. Couldn't find the shroud, it's not sold separately anywhere. So I took the flexible preheater tube, cut the end and flattened it out. Couple of hose clamps, and it works. This should be fine, smog guy said it just has to be attached.

image.jpeg

image.jpeg
 
You want/need vaccuum advance @ part throttle.

Here is the Reader's Digest explanation. For max power & economy, your motor wants as much advance as it can tolerate.

The VA gives you advance at part throttle. At WOT it doesn't do anything and the distributer springs and weights control the advance.

As you back off on the gas....load goes down and vacuum goes up. Because there is less load and gas, your motor will run better w/more advance.

SOOOOO...for example, when you are pushing down on the pedal about 1/4" (high vacuum, no load & no gas), it will run better w.a bunch more advance. Or under the same deal, w.o VA, you can push down on the throttle more, for the same amount of power.
 
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